Spring-motor



'A. F. LOEBKERL SPRING MOTOR.

UNITED STATES PATENT OFFICE.

ALBERT F. LOEBKER, OF KNOXVILLE, TENNESSEE.

SPRING-MOTOR.

Application filed April 8,

To all whom it may con cern Be it known that I, ALBERT F. Lonsxnn, acitizen of the United States, residin at Knoxville, in the county ofKnox and State of Tennessee, have invented a new and useful Improvementin Spring- Motors, of which the following is a specification, referencebeing had to the accompanying draw- My improvement relates particularlyto spring motors comprising a drum-form casing and a shaft on the axialline of the casing and a ribbon-form spring coiled upon itself withinthe drum and having one end joined to the shaft and having the other endengaged directly or indirectly to the casing, the shaft and the casingbeing relatively rotatable.

The object of the invention is to provide such a spring motor in a formadapted to reduce the danger of o'verstraining the spring and avoidingthe binding of the coils of the spring upon each other throughover-tight winding.

In the accompanying drawings,

Figure 1 is a plan lllustrating the principal elements of a spring motorembodying my improvement;

Fig. 2 is a perspective showing the outer end of the main spring and theauxiliary spring and the adjacent wall of the casing, parts being brokenaway;

Fig. 3 is a detail view showing the inner end of the main spring and theadjacent part of the shaft.

Referring to said drawings, A is the drum-form casing. This has abottom, A and a rim, A". E is the axle or shaft. This is of ordinaryform and extends along the axial line of the drum or the casing. It isdeemed unnecessary to show means for rotating the casing or the shaft.

On said shaft is a hook or stud, E. C is the main spring. At is innerend said spring has an elongated aperture, C through which the-hook orstud, E of the shaft, E, extends to make engagement between the springand the shaft. The main spring is of the usual ribbon form heretofore inuse in such drum-shape spring motors, and said spring is coiled uponitself around the shaft and within the casing.

But the outer end of said spring is not joined directly to the rim, A,of the casing, as is the ordinary practice.

An auxiliary spring, D, also of ribbon Specification of Letters Patent.

Patented Sept. 6, 1921.

1820. Serial No. 372,175.

form, is placed between the rim, A and the main spring, C, one end ofthe auxiliary spring being made even with the outer end of the spring,0, and the auxiliary spring ex ending thence in reverse direction aroundthe spring, C, to a stud, D on the inner face of the rim. A rivet, 0extends transversely through the overlapping ends of the two springs andjoins said ends to each other. The stud, D has a head spaced from theinner face of the rim far enough to allow the auxiliary spring to enterthe space between said head and said face. The adjacent or outer end ofthe auxiliary spring, D, has a notch, D which receives the body of thestud, D

In assembling the parts, the main spring and the auxiliary spring arejoined to each other by means of the rivet, C Then both springs areplaced into the casing, the inner end of the main spring being put intoengagement with the hook, E of the shaft, E. Then the outer end of themain spring is drawn for winding far enough to draw the auxiliary springover the head of the stud, D until the V-form outer end of the auxiliaryspring slips over and astride the stud and against the rim, A of thecasing. Then the main spring is released, whereupon it begins to unwindand tends to reverse the movement of the auxiliary spring. But suchmovement is arrested when the outer or notched end of the auxiliaryspring has passed between the head and the adjacent face of the rim andmakes engagement with the body of'the stud, D Then the stud forms anabutment which prevents further movement of the auxiliary spring in thedirection of the strain on the main spring and also crosswise of theauxiliary spring.

Now when either the casing, A, or the shaft, E, is turned in the properdirection to wind the main spring, the outer end of the main spring isheld by the end of the auxiliary spring which is riveted to the mainspring. But such holding is yielding, the free end of the auxiliaryspring allowing its free end to be carried to some extent in thedirection of the pull of the main spring. This elasticity precludes suchdead strain as is placed upon the main spring when the latter isattached directly to the rim and the main spring is wound to the limit.Furthermore, the auxiliary spring allows the attachment of he free endof the main spring to shift from the rim toward the shaft during thewinding of the main spring, this movement toward the shaft continuinguntil the winding has been completed.

Thus the attachment of the outer end of the main spring has allowed. toit a compound elastic movement during the winding of the main spring,one of the components of said movement being concentric to the shaft andthe other being toward the shaft.

I claim as my invention,

1. In a spring motor, the combination of a relatively rotatable casingand shaft, a stud supported by the casing, a main spring located Withinthe casing and surrounding the shaft and having one end secured to theshaft, and an auxiliary spring located between .the main spring and therim of the outer end .of the 'main spring and having its other endnotched and astride said stud, substantially as described.

2. In a spring motor, the combination of a relatively rotatable casingand shaft, a stud supported by the casing, a main spring located withinthe casing and surrounding the shaftand having one end secured to theshaft, and an auxiliary springlocated b tween the main spring and therim of the casing and having one end riveted to the outer end of themain spring and having its other end notchedandastride said stud,substantially as described. 7 I

In testimony whereof I have signed'my name, this 30th day of March,-inthe year one thousand nine hundred and twenty.

ALBERT F. LOEBKER.

